Treatment of fibrous materials with polyamides



Patented Sept. 16, 1952 UNITED fsTATEs PATENT This invention mass to the' 'treatment er fibrous materials especially textile fabrics with synthetic linear pol-yamides and is a continuation-in part of my application SerialNo. 524,195, filed February 26, 1944, and now abandoned.

Synthetic linear po'lyamides are known in commerce as nylon and are organic condensatlon'products which contain a =mu1tiplicity =01 structural units linked in series by amide or thioamidegroupings productzd by a process of manufacture in which non-fibre-forming :forganic substances of lower molecular weightere converted into products of such high molecular weight as to be capable of being formed into filaments which upon cold drawing acquire a true fibre structure recognisable by X-ray examination. When'used in reference to textile art,j}the term "nylon" is not customarily applied to synthetic polyamid'es which are water-soluble.

present invention is concerned with XVHtGY-iHS OI-J uble, high molecular weight or fibre-forming polyamides soluble in "strong acid such as are described in United States patent specification No. 2,071,250, Wallace H. Car-others, patented" February 16 ,'193'7;"United' States patent specification No. 2,071,253, Wallace H. Carother's, pat,- tented February 16, '1937 and United States pat ent specification No. 2,130,948, Wallace H. Carothers, patented September 20, 1938. I,

It will be apparent, therefore, that many of these synthetic linear polvamides are made girom alkylene diamines and higher aliphatic fdic'ar boxylicwacids. Examples of these rare polvalkylenediamine adipates and 'polyalkylenediamine sebacate's. F

Treatment of textile fabrics with solutions of water-insoluble linear polvamide's in or anic solvents and subseouentremoval' of the solvent by evaporation gives aproduct in which the polyamideremains behind as a'iilm and 'ii" the quantitv of polvamide is substantial, the fabric, although'flexible, loses the characteristic feel and handle of a textile material. The principal obiect oi the 'presentinvention is to deposit a waterdnsoluble' synthetic linear polyamide on divided, adherent particles- "wate -i solubl syntheticlinear polyamides will dissolve incom I paratively istron'g'acid and may be precipitated therefrom by the action-of an aqueous mediumand this .fact-is utilised in the present invention 'to precipitate the polyamide on cellulos'ic or non-cellulosic fibrous material's. When' 'soprec'ipitated on the fibrous material, the polyamid'e adheres firmly to the fibres producing a white, opaque effect which is 'fast to laundering and does not render the fibrous material hard or harsh,

Despitethe fact" that synthetic linear. poly-- amides, as is known, are hydrolysed by strong acids, I have found that the "hydrolysis-is so slow that it is possible to apply solutions of them in strong acidsv to fibrous material's'and then "to precipitate the polyamides on to the materials by aqueous media w'ithoutany-material hydroly s'istakin'g place.

The material on which the water insoluble linear polyam-ide hasfbeen precipitated can -b'e passed with or without tension over heated rollers to fuse the polyamide. This is particularly applicable to synthetic linear polyamides of low melting point. It will .be apparent from the aforementioned patent specifications that there is a wide range of water-insoluble synthetic linear polyamides of various melting points. Any of theseeither singly or mixed, soluble in strong acid, may beeuse in carrying out the present invention. a

Among the fibrous materials which the treated are cotton, linen, wool-naturalj silk; viscose yarn, cellulose acetate or mixtures of any of these with one'another-or with synthetic linear polyamide fibresbut the reagent should be'chosen' so as not to damage the m'ater ial treated. The 'fi'brous' materiahmay be in the for m of fabrics, woven *or knitted, o'i-fin any other form, eg as yarn, fibre or sheet; Co,n tinuoussheet materialsuchas paper or wood may also be treated with water-insoluble syn- 'thetic'linear polyamide's by this method.

Fabric which is treated in accordance with the present invention-may be rendered crease: resistant by means or resinous condensation products and, if required; after-treated with swelling agents, or. the "treated fabric may be subjected to other finishing processes. treated 1 with gwateri-n'soluble synthetic -l'inear polyamides in accordance with. the pr'e'sent invention resists shrinking "and' felting after' mill- Among the;strong acidsiwhieh may beu'sed are sulphuric. i-Imdrochloric, nitric, phosphoric 'a'nd ior'micacids but any otheri'strong acids known-to Wool centrated is the acid, the more readily will the polyamide be dissolved but on the other hand the more concentrated acids; hydrolyse poly- The cn centration of the acid used must be sufficient to enable the polyamide to dissolve. The more conamides more readily and this must be taken into consideration in the treatment of textile materials with such solutions. Moreover, the concentration of acid which can be used obviously depends upon the strength of the acid. In the case of formic acid, for example, this may be.

4 a nip to leave 100% of solution on the fabric and then washed off in water and neutralised.

Example-3 2 parts by weight of polytetramethylenediamine adipamide of melting point 278 C. the

manufacture of which is described in British pat- "ent'specificationNo. 474,999, are dissolved in 27 parts by weight of 70 Tw. sulphuric acid. A

cotton or viscose fabric is run through this solution and nipped, off, after which it is washed off in water and neutralised. The so-treated fabric is then run through 140 Tw. sulphuric acid for '5 seconds after which it is washed off again in used anhydrous whereas the form of sulphuric acid commercially known as concentrated sul phuric acid cannot safely be used. i

'A co'nvenient way of treating a textile fabric is to pass it through a solution of the polyamide in sulphuric acid, squeeze it an'dthen'run it into water, whereupon the polyamide is deposited on the fabric as a white pigment. The squeezing will generally be such as to leave 100% by weight of solution calculated on the dryweight of the fabric on the textile; Other pigments which will dissolve in the acid and will be precipitated therefrom by the addition of water (or substances soluble in the acid from which pigments are formed and precipitated by water) may be added to the solution so that co-precipitation takes place.

In order to obtain pattern effects on fabrics, a resist may be printed on the fabric before impregnation with the acid solution. An example of such resists which are preferably insoluble in strong acid, is cellulose'nitrate. Other resists insoluble in strong acid are well known.

Fabrics which have been treated in accordance with the present invention may be given other known treatments such as parchmentising, for example with sulphuric acid or zinc chloride, or other known parchmentising agents, or'may be waterproofed, for example'with one of the known, pyridiniurn compounds. j

I The invention will be more clearly understood from 'the' following examples which illustrate various ways of practising the invention but itwill beunderstood that the invention is not li 1n i e ge mss 1,

-- Example 1 ,2 parts by weight of polyhexamethylenediamine adipamide having a melting point of 278- C. are dissolved in 27 parts .by. weight of 70 Tw. sulphuric acid. A cotton or viscose fabric-is run through thissolution and nipped 01f, after which it is washed off in water-and neutralised.

In the above example wemay use 2 parts by weight of the polymer in parts of 78 Tw. nitric-acid or 10 parts by weight of the polymer in 100 parts ,offormic acid, instead of the s'ul-' phuric-acid, with similar result;

, Example? I V,

A -fine-cambric is'run through a solution of '1 part by weight of"polyethylenediamine"sebacate of melting point 254 C.' the manufacture of which is described in United States patent spe'ci fication 'No. 2,130;948 *'in 25 partsby 'w'eight' of commercial --hydrochloric acid containing 3 by weightof antimony rtrich'lorid'e, passed through water and neutralised. This treatment gives a stifi parchmentised eflect.

Example 4 2 'parts by weight of 'an interpolyamide prepared by heating equimolecular proportions of hexamethylenediamine adipamide and decamethylene diammonium sebacate having a softeningpoint of 112 C., the manufacture of whichis'described in British patent specification No. 559,514, are dissolved in 27 parts by weight of 70 Tw. sulphuric acid. A cotton or viscose fabric is run through this solution and nipped off, after which it is washed off in water and neutralised.- The fabric is then run over a hot roller, with or without stretching, at a temperature high enough to melt the polyamide.

In the above example we may use commercial hydrochloric acid or nitric acid, instead of the sulphuric acid, with similar result.

Ewample 5 I Paper is impregnated with'a solution, in 25 parts by weight of 70- Tw. sulphuric acid, of 1 part by weight of a polymerprepared by heating hexamethylene diammonium adipate and aminostearic acid and having a melting point of 130 C. and an intrinsic viscosity of 0.98, the manufacture of which is described in British patent specificationNo. 559,514; The paper is then im-' mersed in water to precipitate the polyamide thereon. Sheets of paper thus treated can be banded together by heating an assembly of them toa suflicient temperature to bond the polyamide.

- Example 6 1 to.2 parts-by weight of the polyamide prepared from pentamethylenediamine and brassilic acid having a melting point of 176 C., the man-' ufacture of which is described in United States patent specification No. 2,130,948, are dissolved or dispersed in 25 parts'by weight of sulphuric acid of Tw. To the solution is added loose fibre of any description after which the polyamide is precipitated with' water, washed and neutralisedp The mass of-polyamide covered fibres is then heated above the melting point ofthe-polyamide and pressedso that a composite mass of polyamide and fibres is obtained. A1 ternatively, the mass can be rolled into any required thickness and then heated to melt the the-precipitant"for the polyamide wemay use any a ueous Iiquorin' which the polyamide is sub-' stantially insoluble and with which the solution of polyamide is miscible and which does not have any detrimental effect upon the fibrous material treated such as dilute aqueous alkali, e. g. caustic soda or aqueous solutions containing inert salts such as sodium chloride or sodium sulphate.

I declare that what I claim is:

1. Process of treating fibrous material which consists in applying to it a solution of a polyalkylenediamine adipamide in sulphuric acid, removing excess solution and then passing the material into water and thereby precipitating in situ the said polyalkylenediamine adipamide in fine particular form, and neutralising the fibrous material.

2. The process of treating fibrous material which comprises applying to it a solution of two parts by weight of polyhexamethylene-diamine adipamide in 27 parts of 70 Tw. sulphuric acid; wringing out excess solution; washing the material in water and thereby precipitating in situ the said polyhexamethylene-diamine adipamide in fine particular form, and neutralising free acid.

3. The process of treating fibrous material which comprises applying to it a solution of two parts by weight of polytetraethylene-diamine adipamide in 27 parts of 70 'Iw. sulphuric acid; wringing out excess solution; washing the material in water and thereby precipitating in situ the said polytetraethylene-diamine adipamide in 6 fine particular form; and thereafter treating the material with a roller hot enough to melt the polyamide present thereon.

4. The process of treating fibrous material which comprises applying to it a solution containing from one to two parts by weight of waterinsoluble synthetic linear polyamide derived by.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,640,596 Chatham Aug. 30, 1927 2,188,332 Carothers Jan. 30, 1940 2,302,332 Leekley Nov. 17, 1942 2,342,387 Catlin Feb. 22, 1944 2,359,878 Schupp Oct. 10, 1944 

4. THE PROCESS OF TREATING FIBROUS MATERIAL WHICH COMPRISES APPLYING TO IT A SOLUTION CONTAINING FROM ONE TO TWO PARTS BY WEIGHT OF WATERINSOLUBLE SYNTHETIC LINEAR POLYAMIDE DERIVED BY CONDENSATION OF A POLYAMINE WITH A DIBASIC ACID 70* TW. SULPHURIC ACID: WRINGING OUT EXCESS SOLUTION; WASHING THE MATERIAL IN WATER, AND NEUTRALISING FREE ACID. 